A New Dimmable High Power Factor Electronic Ballast System for Compact Fluorescent Lamps (CFL) with Standard Incandescent Phase-cut Dimmers

A novel dimmable electronic ballast system that is compatible with standard incandescent lamp dimmer is proposed in this paper for dimming compact fluorescent lamps (CFL). The proposed electronic ballast features high power factor throughout the entire dimming range even under the operation with incandescent phase-cut dimmer. The electronic ballast power circuit in the proposed system is a single switch circuit that consists of an integrated SEPIC converter to achieve high power factor at the input. The proposed dimming controller uses the phase angle of the dimmer as the input feed-forward parameter and controls the switch of the power circuit using duty ratio control at the same time. As a result, a wide range of light output can be controlled without adjusting a wide range of phase angle from the phase-cut dimmer. Experimental results are given on a 18W CFL from Sylvania to verify with the proposed concept.